This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplemental material
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Lee, J.
Right arrow Articles by Wood, T. K.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Lee, J.
Right arrow Articles by Wood, T. K.
Agricola
Right arrow Articles by Lee, J.
Right arrow Articles by Wood, T. K.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, March 2009, p. 1703-1716, Vol. 75, No. 6
0099-2240/09/$08.00+0     doi:10.1128/AEM.02081-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Reconfiguring the Quorum-Sensing Regulator SdiA of Escherichia coli To Control Biofilm Formation via Indole and N-Acylhomoserine Lactones{triangledown} ,{dagger}

Jintae Lee,1 Toshinari Maeda,1 Seok Hoon Hong,1 and Thomas K. Wood1,2,3*

Artie McFerrin Department of Chemical Engineering,1 Department of Biology,2 Zachry Department of Civil Engineering, 220 Jack E. Brown Building, Texas A&M University, College Station, Texas 77843-31223

Received 8 September 2008/ Accepted 10 January 2009

SdiA is a homolog of quorum-sensing regulators that detects N-acylhomoserine lactone (AHL) signals from other bacteria. Escherichia coli uses SdiA to reduce its biofilm formation in the presence of both AHLs and its own signal indole. Here we reconfigured SdiA (240 amino acids) to control biofilm formation using protein engineering. Four SdiA variants were obtained with altered biofilm formation, including truncation variants SdiA1E11 (F7L, F59L, Y70C, M94K, and K153X) and SdiA14C3 (W9R, P49T, N87T, frameshift at N96, and L123X), which reduced biofilm formation by 5- to 20-fold compared to wild-type SdiA in the presence of endogenous indole. Whole-transcriptome profiling revealed that wild-type SdiA reduced biofilm formation by repressing genes related to indole synthesis and curli synthesis compared to when no SdiA was expressed, while variant SdiA1E11 induced genes related to indole synthesis in comparison to wild-type SdiA. These results suggested altered indole metabolism, and corroborating the DNA microarray results in regard to indole synthesis, variant SdiA1E11 produced ninefold more indole, which led to reduced swimming motility and cell density. Also, wild-type SdiA decreased curli production and tnaA transcription, while SdiA1E11 increased tnaA transcription (tnaA encodes tryptophanase, which forms indole) compared to wild-type SdiA. Hence, wild-type SdiA decreased biofilm formation by reducing curli production and motility, and SdiA1E11 reduced biofilm formation via indole. Furthermore, an AHL-sensitive variant (SdiA2D10, having four mutations at E31G, Y42F, R116H, and L165Q) increased biofilm formation sevenfold in the presence of N-octanoyl-DL-homoserine lactone and N-(3-oxododecatanoyl)-L-homoserine lactone. Therefore, SdiA can be evolved to increase or decrease biofilm formation, and biofilm formation may be controlled by altering sensors rather than signals.

* Corresponding author. Mailing address: Texas A&M University, Chemical Engineering, 220 Jack E. Brown Building, College Station, TX 77843-3122. Phone: (979) 862-1588. Fax: (979) 865-6446. E-mail: Thomas.Wood{at}chemail.tamu.edu

{triangledown} Published ahead of print on 23 January 2009.

{dagger} Supplemental material for this article may be found at http://aem.asm.org/.

Applied and Environmental Microbiology, March 2009, p. 1703-1716, Vol. 75, No. 6
0099-2240/09/$08.00+0     doi:10.1128/AEM.02081-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»